Numerous methods to evaluate user interfaces have been investigated. These methods vary greatly in the attention paid to the users' tasks. Some methods require detailed task descriptions while others are task-independent. Unfortunately, collecting detailed task information can be difficult. On the other hand, task-independent methods cannot evaluate a design for the tasks users actually perform. The goal of this research is to develop a metric, which incorporates simple task descriptions, that can assist designers in organizing widgets in the user interface. Simple task descriptions provide some of the benefits, without the difficulties, of performing a detailed task analysis. The metric, Layout Appropriateness (LA), requires a description of the sequences of widget-level actions users perform and how frequently each sequence is used. This task description can either be from observations of an existing system or from a simplified task analysis. The appropriateness of a given layout is ...

We consider the problem of drawing plane graphs with an arbitrarily high vertex degree orthogonally into the plane such that the number of bends on the edges should be minimized. It has been known how to achieve the bend minimum without any respect to the size of the vertices. Naturally, the vertices should be represented by uniformly small squares. In addition we might require that each face should be represented by a non-empty region. This would allow a labeling of the faces. We present an efficient algorithm which provably achieves the bend minimum following these constraints. Omitting the latter requirement we conjecture that the problem becomes NP-hard. For that case, we give advices for good approximations. We demonstrate the effectiveness of our approaches giving some interesting examples.

. A new algorithm for the linear arrangement problem is described. The goal is to produce linear arrangements of software model diagrams such that the total length of all connections is reduced as much as possible. The algorithm uses the same general numbering strategy as existing algorithms for the highly related problems of bandwidth and profile reduction but is based on a new heuristic that addresses the unique requirements of the linear arrangement problem. Extensive testing is performed with graphs derived from software model diagrams and from structural engineering. The testing indicates that three refinements to the newalgorithmimprove the arrangementsproduced.Thenewalgorithmproduces linear arrangementswithlower total weighted edge length for both classes of test graphs in comparison with several bandwidth and profile reduction algorithms, and for the software model diagrams in comparison with an eigenvalue-based linear arrangement algorithm. The new heuristic is also shown to require slightly less execution time than the frontal increase minimization heuristic used by several bandwidth and profile reduction algorithms, and far less execution time than the eigenvalue-based algorithm. Key words. graph, linear arrangement, bandwidth, profile, diagram layout, algorithm AMS subject classifications. 05C78, 05C85, 68R10 1.

this paper we propose a set of layout operations ensuring exible and convenient interactive editing of GRADE's CD and ER diagrams. The set of our operations includes several procedures oriented on processing of intermediate stages of layouts when incremental design of diagrams prevails. We have also integrated in a single system tools for both, fully automatic layout, and for only direct painting of graphic primitives. In this way we have lled to some extent the gap between the simple painting of separate diagram objects and the fully automatic drawing of entire diagram.

Meta-CASEs are CASE (Computer-Aided Software Engineering) tool factories. For some years, much effort have been spent in this realm to propose a competitive alternative to the traditional CASE framework. Meta-CASEs now benefit from efficient and rich meta-repositories, they support several methods and are multiuser. However, all current meta-CASEs share the same approach of the Graphical User Interface modelling task. We analyze here the new challenges to take up and we propose a new graphical symbolic language (Grasyla) to model the CASE's GUI. Keywords: MetaCASE, CASE tool, graphical symbolic language, meta-modelling, Grasyla 1. INTRODUCTION CASE tools are programs that support software engineers 1 activities during the software life cycle. They can automate some stages (code generation, metrics, model checking, . . . ) or help the software engineers to follow/respect some methodologies. Meta-CASEs are high level compilers/interpreters that produce CASE tools that meet specific ...

this paper we discuss the design and implementation of the Lime* music editor, which provides high-level manipulation of graphically-represented musical information. The discussion should be relevant to the design of other diagram editors, such as systems for the production of maps, schematics, architectural diagrams, tables, equations, and formatted text

Formal descriptions, while difficult for most human readers to understand, are convenient for specifying large software systems, where completeness and consistency are important issues. Informal specifications can offer advantages in readability, but ambiguities and contradictions are unavoidable side-effects. Since a specification often acts as a formal contract between the software developer and the customer, it is essential that both sides be able to fully understand the specification document. Systems have been proposed which help the software client better understand the specification by automatically paraphrasing it in natural language. Metaview is a customizable metasystem that facilitates the construction of software specification environments that can be used to support software specification tasks. This paper describes a strategy for producing natural language descriptions of formal software requirements specifications developed using Metaview specification environments. A c...

Several algorithms have been proposed to draw planar graphs using 2-visibility and Kandinsky Models. Here, we propose three new algorithms implementing these models in linear time using small grid sizes and few bends. These algorithms are all based on the construction of a particular layered spanning tree called Stratification. A linear time algorithm that computes a stratification is also presented.

To provide a flexible and environment independent support for software developers, we propose a CASE (Computer Aided Software Engineering) metasystem, called Metaview. Metaview is based on an extended Entity-Relationship data model that integrates both conceptual and graphical elements of a CASE environment. The EARA/GE (Entity - Aggregate - Relationship - Attribute with Graphical Extension) model and the modeling process are described and exemplified using the Ward and Mellor methodology for realtime systems development. The modeling experience gained from our research and the strengths and weaknesses of our metasystem approach are discussed. Keywords CASE system, meta-modeling, real-time systems development, software development environment, metasystem, Metaview system. Contents 1 Introduction 4 2 The Metaview System 5 3 The EARA/GE Model 7 3.1 The EARA Model Description : : : : : : : : : : : : : : : : : : : : : : 8 3.2 The GE Extension : : : : : : : : : : : : : : : : : : : : :...

this document is to provide a detailed description of the syntax and semantics of the EDL/GE. A general description of EDL/GE program and its conventions is discussed in Section 2. Section 3 details the syntax and semantics of the EDL/GE conceptual definitions, while the graphical definitions are described in Section 4. Finally, the formal syntax of EDL/GE definitions are summarized in Appendix A, and two examples of EDL/GE specifications, the DFD (DataFlow Diagram) and Ward-Mellor environments, are illustrated in Appendix B. 2 EDL/GE: Language Description